Grease and flour a tube (or bundt) panIn a large bowl, cream the butter or margarine and sugar until smooth. Add the eggs, one at a time, beating for one minute after each addition. Sift the flour and add it to the creamed mixture alternately with the whipping cream. Mix until fully incorporated.Stir in the vanilla.Pour into prepared pan and place in a cold oven. Turn the oven to 300 and bake for 80-90 minutes, until a toothpick inserted in the center comes out clean. Cool completely before removing from pan.